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Dendrobium officinale Kimura et Migo (D. officinale) is used as herbal medicine and new food resource in China, which is nontoxic and harmless, and can be used as common food. Polysaccharide as one of the main bioactive components in D. officinale , mainly composed of glucose and mannose (Man p : Glc p = 2.01:1.00-8.82:1.00), along with galactose, xylose, arabinose, and rhamnose in different molar ratios and types of glycosidic bonds. Polysaccharides of D. officinale exhibit a variety of biological effects, including immunomodulatory, anti-tumor, gastro-protective, hypoglycemic, anti-inflammatory, hepatoprotective, and vasodilating effects. This paper presents the extraction, purification, structural characteristics, bioactivities, structure-activity relationships and analyzes gaps in the current research on D. officinale polysaccharides. In addition, based on in vitro and in vivo experiments, the possible mechanisms of bioactivities of D. officinale polysaccharides were summarized. We hope that this work may provide helpful references and promising directions for further study and development of D. officinale polysaccharides. • D. officinale polysaccharides are purified by anion exchange and gel permeation chromatography. • D. officinale polysaccharides possess diverse structures and configurations. • D. officinale polysaccharides exhibit diverse biological activities. • Structure-activity relationship of D. officinale polysaccharides should be addressed in future studies. [ABSTRACT FROM AUTHOR]

A capsular polysaccharides (CPS) producer Bacillus velezensis SN-1 (B. velezensis SN-1) was isolated in Da-jiang, China. We used ultrasonic extraction to obtain CPS from a culture of B. velezensis SN-1 at a yield of 755 mg/L. Using gel permeation chromatography (GPC), CPS was separated into a single peak with a molecular weight of 1.46 × 105 Da. Its structures were characterized by gas chromatography (GC), methylation, Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). The CPS was identified as a polysaccharide with a highly branched main chain of mannose with (1 → 3) connections. Moreover, our results revealed that CPS has the capacity to scavenge DPPH radical, hydroxyl radical, ABTS radical and oxygen radical in a manner that relied on concentration. Anti-neoplastic analysis showed that CPS displayed significant anti-tumor activity towards HepG-2 tumor cells. Above findings indicate that CPS generated by B. velezensis SN-1 may be adapted for use as a natural antioxidant in foodstuffs and as an anti-tumor drug. Unlabelled Image • A purified cell-bound exopolysaccharides (CPS) were extracted from Bacillus velezensis SN-1 in Da-jiang. • The primary structure of CPS was identified by GPC, FT-IR, GC–MS, NMR. • The CPS exhibited potent antioxidant activity in vitro. • The CPS had significant antitumor activities on HepG-2 tumor cells in vitro. [ABSTRACT FROM AUTHOR]